A sad day for my bank account...

[JFP in PA]

It's pretty simple actually; if the cam deviations are steady and outside +/- 6 degrees, you need chain wear pads. If the numbers are outside spec, but bouncing around all over the place, something is moving in the cam drive, usually the IMS shaft.

[Gelbster]

Originally Posted by JFP in PA

It's pretty simple actually; if the cam deviations are steady and outside +/- 6 degrees, you need chain wear pads. If the numbers are outside spec, but bouncing around all over the place, something is moving in the cam drive, usually the IMS shaft.

I was thinking of the more obscure causes like a bent reluctor . worn chin links,weak chain Tensioner(on the IMS to cam chain) , leaking oil past a worn piston/Actuator. I have no idea if any of these are significant ,nor if there are others.
There are some excellent Threads on Rennlist that stress simple things like making sure the engine is thoroughly warmed up before accepting a Deviation reading.
https://www.renntech.org/forums/topic/46101-camshaft-position-1-deviation-of-897/?_fromLogin=1

[JFP in PA]

Originally Posted by Gelbster

I was thinking of the more obscure causes like a bent reluctor . worn chin links,weak chain Tensioner(on the IMS to cam chain) , leaking oil past a worn piston/Actuator. I have no idea if any of these are significant ,nor if there are others.
There are some excellent Threads on Rennlist that stress simple things like making sure the engine is thoroughly warmed up before accepting a Deviation reading.
https://www.renntech.org/forums/topic/46101-camshaft-position-1-deviation-of-897/?_fromLogin=1

Damaged component's tend to push the deviation values one way or the other; the actuators tend to either show no response, or literally go to ridiculous numbers. Sensor failures tend to not give you any values.

Measuring cam deviations has always required a fully warmed up engine, preferably one that has been driven some distance, because the system is oil operated, the flow characteristic's of the oil can alter the data. You need steady state oil to get steady state deviation values.